This invention relates to the field of electrical connectors or probes, and more particularly to the field of connectors for accessing and, in the case of some, interrupting electrical signals going to and from electronic devices mounted in pin grid arrays.
Microprocessor system development tools, such as emulators and logic analyzers, require a connection or probing means for accessing the signal lines used for communication between the microprocessor and its environment, thus permitting the information that these signals contain to be monitored. Furthermore, it is desirable to be able to interrupt some of these signal lines so that information from the development tools can be substituted for information from the microprocessor. Additionally, it is highly desirable to keep the signal paths between the microprocessor and its normal environment, including those paths that are interrupted, as short as possible to minimize undesired electrical effects such as excessive stray capacitance and lengthy propagation times.
For dual-in-line microprocessor pinout arrangements, solutions of the prior art, accomplished most of these objectives to a satisfactory level by placing a target socket for receiving the microprocessor on one side of a circuit board or flexible circuit board immediately adjacent to a connection socket on the other side of the circuit board or flexible circuit board, with a combination of direct runs and interrupted runs connecting the two sockets.
However, as the number of pins on devices increased, high-density interconnection schemes, such as pin grid arrays, have become the norm and the difficulty of accessing so many signals concentrated in so small an area has increased. Accordingly, what is desired is a means for interactively accessing over signal paths of minimum length the signals by which an electronic device having a large number of pins communicates with its environment through a pin grid array.